Field of the Invention
The present invention relates to a heat storage member. More specifically, the present invention relates to a heat storage member having excellent durability and capable of achieving highly-responsive heat radiation and heat absorption by a chemical reaction or physical adsorption and physical desorption between a heat storage material and a reaction medium.
Description of the Related Art
In the related art, the following technique has been proposed. That is, exhaust heat from an automobile and the like is recovered and stored by using a heat storage material, and the recovered and stored heat is utilized to activate a catalyst (a catalyst for disposing exhaust gas) when starting an engine (see Patent Documents 1 to 3). According to such a technique, the heat storage material radiates the recovered and stored heat so that it is possible to early heat the catalyst for disposing exhaust gas and to reduce a time for activating the catalyst. For example, a heat storage device disclosed in Patent Document 1 applies a chemical heat storage material, as the heat storage material, configured to store and radiate heat by a reversible chemical reaction with a reaction medium.
Herein, the chemical heat storage material is referred to as a material capable of absorbing and radiating heat by a chemical reaction. Hereinafter, “chemical heat storage” in the present disclosure is referred to as absorption and radiation of heat by a chemical reaction. The chemical heat storage using the chemical heat storage material has such an advantage that the heat can be stored at relatively high density for a long time and can be reused.
On the other hand, commonly, a potential for a heat pump utilizing physical adsorption and physical desorption of water with respect to zeolite has been shown, and research and development of such a heat pump have been promoted toward a practical application. However, in putting such a heat pump to practical use, efficiency may deteriorate due to low thermal conductivity of the zeolite. Furthermore, a potential for a heat pump utilizing physical adsorption and physical desorption of NH4 with respect to magnesium chloride (MgCl2) has been shown. However, efficiency may deteriorate due to low thermal conductivity of the magnesium chloride.
The heat storage device disclosed in Patent Document 1 applies calcium oxide (CaO) and the like as the heat storage material. Adding water to calcium oxide forms calcium hydroxide (Ca(OH)2) and radiates heat of reaction at the same time. In other words, this reaction is called an exothermic reaction. On the other hand, adding heat to calcium hydroxide causes dehydration reaction of the calcium hydroxide and forms calcium oxide (CaO) and water (H2O). This reaction is called an endothermic reaction. The aforementioned chemical reactions in calcium oxide (or in calcium hydroxide) are reversible. The endothermic reaction is used to recover the exhaust heat, and the exothermic reaction is used to radiate the heat from the chemical heat storage material.                [Patent Document 1] JP 2011-27311 A        [Patent Document 2] JP 2013-112706 A        [Patent Document 3] JP 2015-40646 A        